resource-rich .. countries like Australia, Canada and oil nations have their “stocks” backed by the natural resource. An A$ is a claim on a part of that resource.

In contrast, U.S. is home to the largest concentration of tech companies, who create value from technology, rather than resources underground.

A tourist-dominated economy like Thailand or Macau would issue new “stocks” when their tourist economy expands.

— proven reserve of resources .. new discovery (or depletion) of aggregate reserve in a national economy can directly affect the “book value” of its national stock, leading to appreciation (depreciation)
— foreign reserve .. a national gov can stash away the stocks of other nations, as backing for its own stocks.
Best example .. gold is the standard foreign reserve.

Trade surplus .. if a country enjoys trade surplus for years, it could accumulate a lot of foreign reserve and see its national stock appreciating. A nation’s private exporters deposit foreign currency into local banks. They transfer the currency to the central bank. These exporters typically need to convert the foreign currency in order pay their expenses.
— issuing new stocks or printing money .. I think many governments issue 0.1% new money only when the (national) economy expands by a similar amount.
U.S. government prints money by issuing Fed debts. Japanese? Perhaps similar.

Issuing new stocks during economic decline .. leads to depreciation of the national stock. Even during economic expansion, (excessive) new stock issue can lead to depreciation, when the expansion is not sufficient to support the massive new issue. Investors would realize that a share of this national stock is now diluted.
— demand by foreign investors .. US as an “issuer” has many weaknesses but its “stock” the USD is highly in-demand.
— depreciation due to economic decline.. Even in the absence of new “stock issue”, a stock can lose value if the company is perceived as losing competitiveness.